Influência da contagem de células somáticas e da contagem bacteriana total do leite cru no rendimento da produção de queijos, utilizando metodologia em escala reduzida

Abstract

The evaluation of raw milk quality has become increasingly important for the dairy industry as a way to estimate milk yield. The aim of this study was to evaluate the influence of somatic cell count (SCC) and total bacteria count (TBC) of raw milk on cheese yield, using a small-scalemethod developed in Cornell University (USA). A total of 270 samples of raw milk added with Bronopol preservative were used. The samples were distributed in three SCC levels (below 200,000; 200,000-750,000 and above 750,000 SC/mL) and three TBC levels (below 100,000;100,000-750,000 and above 750,000 CFU/mL). The raw milk samples were submitted to composition analysis (fat, protein, lactose, total solids and solids non fat (SNF), SCC, TBC, freezing point and pH. Cheeses were produced in small scale and cheese whey samples were submitted to compositional analysis (fat, total protein, true protein, lactose, total solids and SNF) and SCC. The SCC increase of raw milk was correlated to decreased protein retention in cheese. High SCC (above 200,000 SC/mL) was correlated to lower levels of lactose in cheese whey and lower dry matter yield. There was no effect of TBC in cheese yield in the experimental conditions used. The small scale method presented a high correlation between the theoretical and predicted yield values, indicating its ability for cheese yield prediction.